Hayward Heater Problems no Error Codes

[Kevink]

I recently replaced the combustion blower on my Hayward H250. The heater turns on fine, ignites with no problem, but then the heater shuts down after about 5 minutes. During the time its on, and after it warms up a bit, the heater makes a faint humming noise. Then it shuts down with no error codes just a service light. When I try to restart it, the blower does not turn on. The only way the blower will turn back on is if I turn the power off and back on at the circuit breaker. Then it will start, ignite, make the humming noise and turn off again with no error codes. I have not inspected the burners or heat exchanger yet, but I'm thinking there's a blockage somewhere. I do not see any water leaking. Any ideas on what this issue could be?

As a side note, the heater was doing the exact same thing before I replaced the combustion blower. The old blower was pretty worn out and brittle so just changed it.

 

[ajw22]

Is the heater NG or LP?

I would check the gas pressures with a manometer. With an old heater you may have a corroded gas line blocking the gas flow. Humming can come from low gas pressure.

You can also have a flame sensing problem. Maybe @swamprat69 @1poolman1 knows how the IDL heater does flame sensing.

The lockout requiring a power cycle indicates an ignition problem.

 

[Kevink]

Thanks I'll get the gas pressure tested. The heater is NG.

 

[1poolman1]

Thanks I'll get the gas pressure tested. The heater is NG.

Its important to check for spider nests in the orifices, especially the one on the far left, right at the igniter on an IDL heater. Usually if that one is blocked the heater won't light, but it could, but the flame-sense rod won't see flame and you could have the problem. The manifold on and IDL heater is the easiest to remove and replace of all the heaters I have worked on.

Remove the gas line from the main gas valve. This will require closing the external gas valve, opening any union in the line, unthreading pipe from the main gas valve. There will be about 6 screws that hold the manifold in place. A 5/16" socket or nut driver will easily remove and replace those. You will need either a 3/8" or 7/16" wrench to remove any clogged orifices (Hayward used different sizes occasionally so have both available). Always remove the clogged orifice and push whatever is blocking it out toward the back. Us a copper wire, a toothpick, small twig, so as to not scratch the orifice. You don't want to push the debris into the manifold, it will just move and block somewhere else.

On reassembling, be sure to use some pipe sealant for gas, a small tube of RectorSeal #5 is about $4-5. Be sure the union is tight, no sealant is used. After you get it all assembled, turn the external valve on and check for leaks with a bit of soapy water at each joint you disturbed. You will see how far the pipes were threaded into the fittings by whatever was used to seal initially. Use that as a guide. It is especially important to not get too tight going into the main gas valve in the heater, it will crack and need to be replaced. Always leave at least three threads showing outside any fitting.

This probably sounds harder than it really is, but if you are not comfortable working on gas plumbing, call a pro. That is the safest way if you are not the DIY type. Most likely, the tech that checks your gas pressure could do this if the gas pressure is not the issue.

 

[Kevink]

This probably sounds harder than it really is, but if you are not comfortable working on gas plumbing, call a pro. That is the safest way if you are not the DIY type. Most likely, the tech that checks your gas pressure could do this if the gas pressure is not the issue.

Great, thanks! I finally had some time to check the orifices and everything seems to be clean.

Here's an update: Today I started the heater and it worked fine for about 8 minutes. After about 1 minute from starting, I heard the hum again which you can hear in the link to the video I posted. Then the hum went away and it worked fine until it shut down. When it initially shut down there were no error messages. But then it tried to restart, and I eventually got the flashing AO error message. From that point, the heater would not start again unless I turned off the circuit breaker.

Dropbox Video of Hayward Heater Hum Noise

I've read quite a few pool heater threads and I can't find any issue like the one I'm having. Very frustrating. The heater turns on, ignites, gives heat, but then shuts down after a few minutes. Maybe time to call a pro.

 

[Kevink]

Question: If the heat exchanger had a blockage or some issue where it would cause the heater to overheat and shut down....roughly how long would this take??

I ask because I can get the heater to function properly for roughly 14 minutes ( 60 degrees here in Texas). Then it shuts down completely and will not start again unless I turn off power at the circuit breaker. No error codes. The service light comes on after shut down but goes out when I try to start it again. I'm to the point where it I think it may be either the control board that's bad......or something with the heat exchanger. I have NO banging noises or movement, it seems to be running normal just before shut down.

I've had a pool tech come out twice and he couldn't figure out the issue (I need a new pool tech for sure.... but anyway). Gas and water flow are fine. I've replaced several parts which were marginal or in bad shape....new bypass valve and flow thermostat, new hi limits, and a new vacuum switch. New combustion blower. The heat exchanger is old but it looks pretty decent compared to some of the pics I've seen here and elsewhere. No leaks. Like I said, once I reset the power, the heater starts, ignites and works fine for about 14 minutes then just shuts down. So, if there was a problem with the exchanger, would it happen sooner or at any time?

 

[1poolman1]

The "hum" sounds like an issue with the blower. "An AO code on a Hayward heater is a blower vacuum switch open error and simply means that the blower prover switch did not close after the blower started."

It is discussed in this thread:

Hayward H250FDN AO code

Hello everyone, I have a Hayward H250FDN spa water heater and now all of a sudden an "AO" code appeared . I replaced the boards a couple of years ago and now this has happened. Any help would be greatly appreciated, Thank you.

www.troublefreepool.com

 

[Kevink]

The hum absolutely was the blower. I got a replacement under warranty from Hayward and the one they sent me was worse than the one I had. The squirrel cage rubbed up against the housing and got stuck several times. The shaft was cockeyed. But that's another story. I do NOT have an error code now. The heater just turns off after 14 minutes or so.

 

[1poolman1]

The hum absolutely was the blower. I got a replacement under warranty from Hayward and the one they sent me was worse than the one I had. The squirrel cage rubbed up against the housing and got stuck several times. The shaft was cockeyed. But that's another story. I do NOT have an error code now. The heater just turns off after 14 minutes or so.

Have you cleaned the "flame sense" rod? It should be the last item on the right, above the burners with the single wire running to it. The best thing to use is, I kid you not, a newer dollar bill (or what ever denomination you may have). They are just abrasive enough to remove most coatings that may build up without removing the protective coating on the rod itself. Don't use sandpaper. That's an old HVAC trick.

 

[Kevink]

I haven't touched the flame sensor but will definitely try that today. Thank you.